Molecular assembly of an achiral phosphine and a chiral primary amine: a highly efficient supramolecular catalyst for the enantioselective Michael reaction of aldehydes with maleimides.
Molecular assembly of an achiral phosphine and a chiral primary amine: a highly efficient supramolecular catalyst for the enantioselective Michael reaction of aldehydes with maleimides.
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DOI：
10.1002/asia.201300141
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发表时间：
2013-06
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通讯作者：
Wei Yang;K. Jiang;Xing Lu;Huameng Yang;Li Li-Li;Yixin Lu;Li‐Wen Xu
中科院分区：
文献类型：
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作者：
Wei Yang;K. Jiang;Xing Lu;Huameng Yang;Li Li-Li;Yixin Lu;Li‐Wen Xu
辛可尼定衍生的伯胺和三苯基膦（CD-NH 2/PPh 3）的组合催化剂体系在醛与马来酰亚胺的Michael反应中表现出高的催化性能，从而以优异的产率（高达99%）和对映选择性（> 99%ee）提供相应的官能化醛。更有趣的是，膦在提高手性伯胺催化的Michael反应中的对映选择性方面的重要性被揭示出来。进一步探讨了二元有机催化体系促进的Michael加成反应机理的起源。根据实验结果和光谱分析，如UV/维斯、荧光发射（FL）、NMR、圆二色谱（CD）和ESI-MS，我们发现膦和伯胺的分子组装在该不对称选择性反应中起着至关重要的作用，其中通过金鸡纳生物碱的非共价分子相互作用形成可能的超分子复合物作为有效的手性催化剂，用三苯基膦衍生伯胺。
A combined catalyst system of a cinchonidine-derived primary amine and triphenylphosphine (CD-NH2 /PPh3 ) exhibited high catalytic performance in the Michael reaction of aldehydes with maleimides, thereby affording the corresponding functionalized aldehydes in excellent yields (up to 99 %) and enantioselectivities (>99 % ee). More interestingly, the significance of the phosphine in enhancing the enantioselectivities in the chiral-primary-amine-catalyzed Michael reaction was revealed. Furthermore, we explored the origin of the reaction mechanism in the Michael addition promoted by the dual organocatalytic system. On the basis of experimental results and spectroscopic analysis, such as UV/Vis, fluorescence emission (FL), NMR, and circular dichroism (CD) spectroscopy, as well as ESI-MS, we found that the molecular assembly of phosphine and primary amine played a crucial role in this enantioselective reaction, in which a possible supramolecular complex was formed as an effective chiral catalyst through noncovalent molecular interactions of a cinchona alkaloid-derived primary amine with triphenylphosphine.